Which SIL assignment method considers solely the consequences of an incident?

• A. Risk Matrix
• B. Consequence Only
• C. Modified HAZOP
• D. Fault Tree Analysis

Answer: (B)

The method that focuses solely on the consequences of an incident is the Consequence Only approach. This method evaluates the severity of potential outcomes from hazardous events without factoring in their likelihood or probability of occurrence.

In functional safety, understanding the different dimensions of risk is crucial, and while many risk assessment methods consider both frequency and severity, the Consequence Only method exclusively analyzes the potential consequences. This can be particularly useful in situations where the likelihood of an incident is determined to be certain or when aiming to develop a severe consequence-oriented safety strategy.

The other methods mentioned involve additional factors beyond merely the consequences. For instance, the Risk Matrix typically evaluates risks based on both the probability of occurrence and the severity of consequences to prioritize risk management efforts. Modified HAZOP, a variant of the Hazard and Operability Study, focuses on identifying hazards through deviation analysis, incorporating both the cause and consequence of those deviations. Fault Tree Analysis investigates causes leading to a specific undesired event, intertwining both the likelihood of the causes and the resulting consequences. Hence, the Consequence Only method distinctly stands out by concentrating exclusively on what happens when incidents occur, making it the right choice in this context.